In Hinduism, Agastya is a legendary Vedic sage or rishi. Some say that it was the sage Agastya who first brought and popularized the Vedic religion to south India.
Agastya and his clan are also credited to have "authored" many mantras of the Rig Veda, the earliest and most revered Hindu scripture, in the sense of first having the mantras revealed in his mind by the Supreme Spirit Brahman.
In some reckonings, Agastya is also said to be one of the greatest Seven Sages or Saptarshis. The word is also written as Agasti.
Agastya was a great devotee of Lord Shiva. After Agastya reached the south, in answer to his prayer for revelation on the classical language of South India, Lord Shiva himself taught the classical Tamil language to Agastya.
Agastya is said to have attended Tamil Sangam (convention) and staged his work the Agattiyam or Agastyam, reputedly one of the earliest treatise on Tamil grammar. In the 2500-year old Tamil Sangam, Agastyakoodam has a history of being homet Siddha medicine and it is said to be the home of Agastya.
He is considered as the first and foremost person of Siddha. He is considered the guru of many other Siddhars. He is also called Kurumuni, meaning short (kuru) saint (muni). His contributions were to the field of Medicine (Siddha) and Astrology - especially Nadi Jodhidam(Jos(i)yam or Jothisyam). He is said to have lived for over 5000 years, and that one of his medicinal preparations, Boopathi Kuligai, is so powerful that it can even bring the dead back to life. Two of his students and disciples were Therayar and Tholkappiar.
The Lalitha sahasranama, which describes the 1000 names of the mother Goddess (Known commonly as Gowri, Parvati or Durga), was first revealed to the world when Hayagriva, a manifestation of Vishnu, taught the same to Agastya. Agastya is said to have composed the Aditya Hridayam, a hymn to Surya, and taught the same to Rama just before the war between Rama and Ravana.
The king of Vidarbha had a daughter by name Lopamudra. She was exceptionally beautiful and of excellent character. Sage Agastya heard about the princess and approached the king for his daughter’s hand in marriage.
The king was in two minds. He was reluctant to give his darling daughter to a sage living in forest. At the same time, he feared the wrath of the powerful sage. Lopamudra sensed the dilemma of her father. She told the king. “Father, do not worry on my account. I shall gladly be the wife of this sage”.
Thus, Agastya got the pretty princess of Vidarbha as wife. He asked his wife to cast away all her rich clothes and precious jewellery. They were going to live in a forest where such expensive costumes would have no meaning.
But, the sage was worried that his wife did not bear any children for him. He asked her for the reason. Lopamudra replied. “Dear husband, our way of life does not suit me to bear children and bring them up. If you want children, get me a decent place to live and wealth for their upbringing”. Agastya told her of his poverty. Where could he get the money for a house and other expenses?
In search of Wealth:
But, the sage wanted to get children badly. So, he set out begging for money. He approached a king and pleaded for help. The king replied. “Sage, I would have been only too pleased to give you anything you ask for. But, please look at my books account. See for yourself that what I collect as taxes are spent fully for the cause of people. Nothing is saved. If you insist, I will have to collect more taxes”. But, the sage did not want ordinary people burdened on account of him.
Ilvala and Vatapi:
Ilvala once requested a Brahmin to bless him for getting a son as powerful as Indra, the king of gods. The Brahmin refused the request right away. That made the demon angry. He wanted to take revenge on all Brahmins because one of them refused to grant him his wish.
Agastya and the kings had heard about the trick played by the demon brothers. The kings were apprehensive. But, the sage was unnerved. As usual, Ilvala offered the special dish of goat meat. Agastya ate the dish to his fill. The kings did not touch the meat.